Maybe it’s in the National League Central, where the Milwaukee Brewers and St. Louis Cardinals are racing toward a spot in the playoffs. Since football season is near, maybe it’s Auburn-Alabama, or Seahawks-49ers. Maybe we’ll see it played out on Sunday as the PGA Championship comes to a close.

While each of those rivalries are compelling, the best one is happening at a pool in Irvine, California this week. Katie Ledecky and Missy Franklin, each Olympic gold medalists, faced off in the 200-meter freestyle at the U.S. national championships.

Franklin won it last year. Ledecky easily won this time. Afterwards, she acknowledged the rivalry, but that it’s not exactly a heated, angry one.

No, this isn’t a rivalry that will encourage trash talking. These two are more likely to give each other a hug than a sidelong glance. Even as Ledecky heads to Stanford next season, and Franklin heads into her sophomore year at California, the rivalry won’t become as nasty as it has been historically between their schools.

This is not the best rivalry because of how heated it is. It is the best rivalry because it achieves what real, pure rivalries always do: the athletes involved are pushing each other to levels they otherwise would not have reached.

This is what the best rivalries do. Where would Bird be without Magic? Or Sampras without Agassi?

“I’m still learning how to swim against her,” Franklin said. “I’m really glad I have her in that race to push me.”